The present invention relates to an electrostatic charger device for electrostatically charging an image bearing member in an image forming apparatus configured to perform electrophotographic image formation and, more particularly, an electrostatic charger device provided with a cleaner member for cleaning a surface of an electric discharge member. The present invention also relates to an image forming apparatus incorporating such an electrostatic charger device.
Electrostatic charger devices include an electrostatic charger for electrostatically charging a photoreceptor drum as an image bearing member, an electrostatic pre-charger for imparting electrostatic charge to a toner image on an intermediate transfer belt as an image bearing member, and like electrostatic chargers. Such an electrostatic charger device has an electric discharge member such as a discharge wire or a plate-shaped electrode. The electrostatic charging efficiency of such an electric discharge device decreases as the surface of the electric discharge device becomes stained by toner on an image bearing member at every discharge. In order to prevent the electrostatic charging efficiency from decreasing, the electrostatic charger device needs to clean the surface of the electric discharge member.
Among conventional electrostatic charger devices there is an electrostatic charger device of the type which includes an operating rod having one end provided with a cleaner member m formed of CR rubber (chloroprene rubber), urethane foam, or the like and the other end provided with a handle, as disclosed in Japanese Patent Laid-Open Publication No. H10-078692. The operating rod is capable of reciprocating the cleaner member along the electric discharge member while pressing the cleaner member against the electric discharge member. By reciprocating the operating rod along the electric discharge member, the cleaner member cleans the surface of the electric discharge member.
When formed of a resin wire material or a metal wire material having a small sectional area for cost reduction or size reduction, however, the operating rod has a lowered rigidity and hence is easily bent by the operating force exerted for reciprocal movement. When the operating rod is bent toward the image bearing member and brought into contact with the image bearing member, the operating rod damages the surface of the image bearing member.
A feature of the present invention is to provide an electrostatic charger device which fails to damage the surface of the image bearing member even when the operating rod has a lowered rigidity, as well as an image forming apparatus incorporating such an electrostatic charger device.